Elucidation of Reaction Mechanism and Evaluation of Rate of Iron Oxide Reduction with Gas Mixtures including Methane

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Iron oxide pellets were used as iron ore samples because of the well-known reduction kinetics. The pellets weighing 2kg were packed in a reactor and reduced isothermally with gas mixtures such as CH_4-N_2, CH_4-H_2O-N_2, and CH_4-CO_2-N_2. Elucidation of the reaction mechanism and evaluation of the reduction rate were carried out on the basis of the kinetic analysis using reaction models. Unreacted core shrinking model for three interfaces were adopted to the experimental reduction data of single particles with H_2-H_2O-N_2 or CO-CO_2-N_2 gas mixture, and rate parameters for H_2 or CO reduction were evaluated. Thermal decomposition of methane with iron catalyst was experimentally carried out. Optimum conditions for iron oxide reduction with CH_4 bearing gas mixtures were examined and fundamental data for analyzing pre-reduction of iron oxide with coal carbonization gas were obtained ; carbonizing conditions of coal and reduction conditions of iron oxide were simultaneously investigated to present the optimum ones.